In the current 3GPP release 4 architecture, both core-network (CN) and the interfaces connecting radio network controllers (RNC) and CN are IP-based, and during handling of the voice calls traffic, for example, fixed IP technique has been employed, that is, an exclusive IP-address is assigned respectively to each wireless communication unit (RCU) requesting a voice call such as a PSTN network phone and a mobile subscriber UE (User Equipment), subsequently leading to deterioration of system resources utilization efficiency. As is known, IP address resources are quite scare in the wireless communication system employing the all-IP architecture, therefore a new technique differing from conventional fixed-IP of assigning to each RCU that requestes a voice call is necessary.
In addition thereto, the system architecture in the prior art is disadvantaged by adopting different protocols for different services such as CS and PS, for example, the Megaco-protocol-based CS service transmission method and GTP-protocol-based PS transmission method in current 3GPP Release 4 architecture. This will make the system architectures and the type of the service not uniform, thus leading to reduction in utilization efficiency of communication resources and service efficiency.